When I look at webmin's "system information" page it tells me that the CPU is much greater than when doing
top in the terminal? Why? What is going on?
Today the server also broke down
I recommend not to wonder what web-based tools show as a status. The information being shown there can be outdated (usually by a few seconds, often depends on how fast your browser loads the page).
Your screenshot of top seems to show a system which is mostly idling and not running any resource intensive processes.
I guess you screenshotted top before looking and your web tool? Those web tools normally cause a high load when reading out the stats from your system, but that is only temporary. The tools then show a higher load than there really is on the system since the web tools themselves cause this high load for a short amount of time.